Private-equity giants Leon Black and David Bonderman may be holding a losing hand at Caesars Entertainment.

The company, America’s largest casino chain, owned by the investors’ PE firms, has revealed that it is the subject of a money-laundering probe by the IRS.

News of the tax agency investigation comes days after Caesars revealed federal and state regulations have drawn a bead on its Las Vegas casino for possible violation of the Bank Secrecy Act and after state regulators in Massachusetts rejected the company’s application for a casino license in the Bay State.